Valve tip hardening machine



Dec. 25, 1934. w. H. SPIRE 1,985,805

VALVE TIP HARDENING MACHINE Filed May 9, 1933 Patented Dec. 25, 19341,985,805 VALVE TIP HABDENING MACHINE William a. spin.

Thompson Ohio, a corporation of Ohio Application May 9, 1833, Serial No.670,181

This invention relates to means for heat treating the tips of the stemsof poppet valves, such as are used in internal combustion engines, andis a division of my copending application Serial No. 582,482, filedSeptember 12, 1931, for Valve tip hardening machine and method.

The means disclosed are not limited in their application to the heattreatment of valve stems, and many other applications 01' my inventionwill readily suggest themselves.

The tips of that end of a poppet valve stem that engages the valveoperating mechanism of internal combustion engines is usually given afinal heat treatment following the mechanical operations that give thevalve its form The end of the stem is placed between -a pair of opposedelectrodes, current is sent through the tip of the stem to raise it to adesired temperature,

and then the valve is placed in a quenching bath.

It is obvious that the opposed jaws of the clamping electrodes must bespaced apart to prevent their shortcircuiting the path of the currentthrough the clamped valved stem, and it follows that the current flowingfrom electrode to electrode through the stem will tend to follow oneshort and relatively narrow path,with consequent overheating of themetal in that path,due to the magnetostriction of the current path. Theelectrodes do not clamp each succeeding specimen in precisely the sameway: previous mechanical treatment of the stem tip variously afi'ectsits conductivity to current, so to produce similar heating effect of thecurrent in the same time would require extraordinary skill on the partof the operator of the machine, and tedious adjustment of the currentintensity. It will be evident that when the major portion of thecurrent, and of the heat energy, flows along a definite and relativelynarrow path, the metal in that path will flow and adjust itself withinthe cross-section of the stem in a manner different from that of thecolder metal bordering it, and that when the stem is quenched in thehardening bath, the final condition of the periphery and of the internalstructure of the cell cannot be satisfactory.

I have heretofore sought to overcome the disadvantages mentioned byturning the stem on its longitudinal axis, but this necessitatedrepeatedly opening and closing the clamping electrodes and the currentsupply, and was unsatisfactory because of the labor involved, and timeconsumed, the increased wear of the electrodes and switching mechanism,and the fact that the thermal and electrical conductivity of eachsucceedingpath was aifected by nu-momma what happened in current. myinvention to provide a maprevious g heat treatment to the tips of auniformly good product may unskilled operator.

d further important objects of nur will appear in the description of myFigure 1 is a schematic diagram of the instrumentalities em Figures 2and 3 flow through the during the operati In the drawing: The numeral 1tional step-by-s comprises a wiper a spring 12 b a rachet 15 and bodyingmy invention.

are end views indicating heat end of a heated valve stem on of mymachine.

0 indicates, generally, a conventep switch 7 mechanism, which arm 11urged forward against y a pawl 13 engaging the teeth oil actuated by amagnet 14. The

wiper arm successively makes contact with a plurality of the arm is Theconta nected to a r operated switch 20 treat a batch of moves selectorswitch 2 spaced contacts 16 the wiper arm is prevented by restored toits orig the detent is raised by a relea Retraction of a detent 17, andinal position when sing magnet 18.

cts 16 are extended, or are conow of contacts 19 so that a manually aybe moved to make conthem.

is first put in service to valve spindles, the operator 0 to the zeroposition in contact with the contact indicated by zero. The

wiper arm should The operator now then be in its initial position.closes a foot-switch 21,

thereby causing current to fiow from the alternating current supplymains along wire 22,

through switch 20, wire 23, thro back to main wire solenoid 24 moves 27,thereby providing a circuit through solenoid 28, to retract a c andthereby retract one of a pair through wiper arm 11, along ugh solenoid24, of switch 25, and

26. Current fl switch 25 to owing through close contacts from wire 22ore 29 thereof, of jaws of the electrodes 30, through a connecting linkmechanism 31.

It is a simple matter both of the jaws are and this is usually done Thetip portion now inserted between foot-switch 21 is jaws 30 close toclamp the valve under the urging of a sprint 33. or

similar means.

ing transformer 40 The jaws of the electrodes 30 are recessed, asindicated by numerals 34 on Figures 2 and 3, so that the jaws mayreadily accommodate themselves to the clamping of round stems of severaldifferent diameters, and also to define definite current paths throughthe crosssection of the stem adjacent opposed margins of the stem.

The operator now moves the selector switch to, say, contact 3, and againcloses the foot switch 21.

There is now, at the outset, no current path through the selectorswitch, and switch 25 is in its normal position, closing contacts 35.Cur rent now flows from wire 26, through solenoid 36 of switch 3'7,through contacts 38 of switch 39, through contacts 35 of switch 25, andback to wire 22. Current flowing through solenoid 36, closes switch 37,and thereby energizes the heatwhich is connected to the electrodes 30.When the current flows through the electrodes 30 and the tip of the stemof the valve 32, the tip becomes heated, and when the tip is viewed fromabove the two paths of greatest current intensity are clearly indicatedby two transversely extending white regions with a duller regionbetween, as indicated on Figure 2.

Positioned above the heated stem is a photoelectric cell 41, of aconventional type, with a lens 42 to direct rays from the heatedmaterial to its light-sensitive electrode. The cell 41 is suitablyconnected to a power source through a conventional amplifier 43, toamplify the current flow of the cell. Connected to the cell 41 is asolenoid 44 of the switch 39, so that upon the current through the cell41 attaining a predetermined intensity, indicating a predeterminedtemperature of the heated work, the solenoid 44 causes switch 39 tointerrupt contacts 38, thereby de-energizing solenoid 36, and causinginterruption of the heating current.

Solenoid 44 also causes switch 39 to close its contacts and therebyestablish a circuit from a direct current source, through wire 46,contacts 45, magnet 14, and wire 47 to advance the wiper .arm 11 onestep forward.

When the supply circuit of transformer 40 is interrupted by this actionof cell 41, the heat energy in the heated work diffuses uniformly overthe cross-section of the material, and the .whole end takes on theappearance of that of the intermediate strip of Figure 2, as isindicated in Figure 3. Immediately upon this uniform distribution of theheat energy taking place, the current through the cell 41 decreasesslightly, and in consequence of this current decrease, switch 39 returnsto its normal position to close contacts 38 and thereby close thecircuit through solenoid 36 to close the transformer supply switch 37.The aforementioned cycle, changing the appearance of the heated end fromthat indicated in Figure 2 to that indicated in Figure 3, is repeated,with the wiper arm 11 advancing a step when the cell 41 breaks theheating current through switch 39.

When the wiper arm 11 has advanced to make contact with a contact thatis connected to the selector switch 20, a circuit is again closedthrough wire 22, wire 23, solenoid 24, to wire 26, to move switch 25 toclose contacts 2'7 and thereby energize solenoid 28 to retract anelectrode jaw and drop the valve 32 into a hardening bath 48.

The operator now inserts another valve between the open jaws, and thenmomentarily releases the foot switch 21 to de-energize a solenoid 49,connected in parallel with wires 22 and 26, to

release a switch 50, to close contacts 51, and thereby establish acircuit through the detent releasing magnet 18 and wires 46 and 47. Thewiper arm 11 returns to its original position, and now, without anyeffort of the operator other than to keep the foot switch 21 closed, themachine automatically gives the stem the desired number of heat cyclesand then drops the valve into the hardening bath.

The proper number of cycles of alternate heating and heat flooding ofthe stem is determined, naturally, by the history of previous mechanicaltreatment given to it, but when a batch of formed valves are put throughthe machine they are usually inserted only a few seconds apart.

It is a simple matter to adjust the responsivity of the cell and of theassociated amplifier and relays to obtain any reasonable variation inthe heat application and heat fiooding periods to properly treat stemsof different diameters and of different materials.

It will be understood that the conventional step-by-step mechanismdescribed may be variously modified while retaining, in substance, itsfunction in causing interruption of the heating current at the end 01 apredetermined number of heating cycles.

When a batch of material comprises stems or rods which are substantiallyalike in their history of previous treatment, in diameter, and incomposition, a given number of heating cycles usually takes place in afairly definite period of time, so it would then be possible to arrangethings so that the heating current is interrupted and the jaws opened todrop the rod or stem at the end of a certain period following theclosing of the foot switch.

I am aware that many changes may be made and numerous details ofconstruction may be varied through a wide range without departing fromthe principles of this invention, and I, therefore, do not purposelimiting the patent granted hereon otherwise than necessitated by theprior art:

What I claim is:

l. A machine for heat-treating the tips of valve stems, or the like,said machine comprising spaced stem-clamping electrodes, heating currentsupply circuits including switch means connected to said electrodes toheat a stem-tip clamped therebetween, means responsive to thetemperature of the heated tip to govern movement of said switch means,and a step-by-step switch mechanism cooperable with said heating circuitmeans and said temperature responsive means to produce cyclic variationsin the flow of heating current through the heated tip.

2. A machine for heat-treating the tips of valve stems, or the like,said machine comprising spaced stem-clamping electrodes, heating currentsupply circuits including switch means connected to said electrodes to,heat a stem-tip clamped therebetween, means responsive to thetemperature of the heated tip to govern movement of said switch means, astep-by-step mechanism cooperable with said heating circuit means andsaid temperature responsive means to produce cyclic variations in theintensity of the heating current through the heated tip, and to causerelease of the clamped stem at the end of a predetermined number ofheating cycles.

3. A machine for heat-treating the tips of valve stems, or the like,said machine comprising stemclamping electrodes, heating current supplycircuits including switch means connected to said electrodes, means tocause successive cyclic variations in heat flow in the heated tip for apredetermined number of cycles, said means comprising means responsiveto the temperature of the heated tip to alternately close and open theheating current circuit, and means cooperable with said temperatureresponsive means to interrupt said heating current supply circuit aftera predetermined number of cycles.

4. A machine for heat-treating material to produce alternate periods ofheat application and heat diffusion through the material, said machinecomprising spaced electrodes, heating current supply circuits includingswitch means connected to'said electrodes to send current through saidelectrodes and material positioned therebetween for heat treatment,temperature responsive means cooperable with said current supplycircuits to produce alternate periods of heat application and heatdiffusion through the heated material, and means cooperable with saidtemperature responsive means and said heating current supply circuits tointerrupt the heating circuit upon the termination of a number of heatapplication and heat diffusion cycles.

5. In combination, spaced electrodes, heating current supply circuitsincluding switch means connected to said electrodes, said electrodesincluding portions for clamping material to be heated disposed betweensaid electrodes, temperature responsive means responsive to thetemperature rent supply circuits to produce alternate heat applicationand heat diffusion through the heated material, and means cooperablewith said temperature responsive means and said current supply circuitsto interrupt the heating'current and to cause movement of saidelectrodes to release the material clamped therebetween upon thetermination of a number of heat application and heat diffusion cycles.

6. In combination, spaced electrodes, one of said electrodes having arecess in its working face thereby defining spaced current conductingfingers on the working face of the electrode, heating supply circuitsincluding switch means con-: nected to said electrodes, said fingersbeing adapted to clampingly engage material to be heated positionedbetween said electrodes, temperature responsive means responsive to thetemperature of the heated material cooperable with said current supplycircuits to produce alternate heat application and heatdiffusion throughthe heated material, and means cooperable with said temperatureresponsive means and said current supply circuits to interrupt theheating current upon the termination of a number of heat application andheat diffusion cycles.

7. In combination, spaced electrodes for clamping material to be heated,heating current supply circuits including switch means connected to saidelectrodes, means to define spaced current paths of relatively highcurrent intensity through the material, said means comprising spacedconducting fingers on the clamping face of said electrodes, means toproduce periodic variations in the current intensity whereby the heatedmaterial is alternately subjected to relatively high heat transfer alongspaced parallel paths and diffusion of heat at a substantially uniformlevel, said means comprising temperature responsive means responsive tothe temperature of the heated material cooperable with said supplycircuits to produce cyclic variations in current intensity, and meanscooperable with said temperature responsive means to interrupt thecurrent supply circuits upon the termination of a number of cyclicvariations in the current intensity.

8. A machine for heat-treating a member to be heated, a heating currentsupply circuit connected to heat the member, means to selectivelycondition said supply circuit and thereby produce alternate heating andheat diffusion in the member, means to selectively condition said supplycircuit and thereby produce alternate heating and heat diffusion in themember, said conditioning means comprising means responsive to thetemperature of the member, and timed means cooperatively connected tosaid temperature responsive means and to said circuit.

9. A machine for heat-treatment of a member to be heated, movable meansto hold the member during treatment, a current supply circuit to heatthe member, means to selectively condition said supply circuit andthereby produce alternate heating and heat diffusion in the member, saidconditioning means comprising means responsive to the temperature of themember and timed means cooperatively connected to said tempera- ,tureresponsive means and to said circuit, and means operably connected withsaid temperature responsive means to effect movement of said movablemeans.

10. In combination, means for heat-treating a metal which is part of aheating circuit to produce cylic heating of and diffusion of heat in themetal, said means comprising a heating current circuit, switch means insaid circuit, means responsive to the temperature of the heated metal,and timed means in circuit connection with said switch means and withsaid temperature responsive means and cooperable therewith toalternately close and open said circuit, respectively.

11. In combination, means for heat-treating a metal which is part of aheating circuit to produce heating of and diffusion of heat in themetal, said means comprising a heating current circuit, means responsiveto radiant energy emitted by the heated metal, and timed means connectedto said heating circuit and to said energy responsive means arrangedcooperable with said energy responsive means to determine the length ofthe heat-treating period. I

12. In combination, means for heat-treating a metal which is part of aheating circuit to produce heating of and heat diffusion in the metal,said means comprising a heating current circuit. means responsive toradiant energy emitted by the heated metal. and means adapted to varythe intensity of the current in said heating circuit connected to saidradiant energy responsive means to maintain the temperature of theheated metal within predetermined limits.

13. In a machine for heat treating a metallic rod which is part of aheating circuit to produce heating of and diffusion of heat in the rod.a heating current circuit, electrode means movable to retain the rod inthe circuit during the heat treatment. means responsive to radiantenergy emitted by the rod. and means connected cooperable with saidelectrode means and said energy responsive means to effect movement ofsaid electrode means.

WILLIAM H. SPIRE.

